Question

a scientist is trying to determine the relationship between clams, snails, and squid. when she generates a molecular clock, she is surprised to see that clams and squid are more closely related than clams and snails. which did the molecular clock data show?

• clams and squid have been evolving separately for a longer time than clams and snails.
• clams and squid have been evolving separately for a shorter time than clams and snails.
• clams and snails have more in common genetically than clams and squid.
• clams and snails are more similar in related structures than clams and squids.

Explanation:

Molecular clocks measure genetic divergence over time; closer evolutionary relationships mean less time evolving separately. If clams and squid are more closely related, they split from a common ancestor more recently (shorter separate evolution time) than clams and snails. The other options contradict this logic: longer separate time would mean less relatedness, more genetic commonality would mean closer relation, and structural similarity isn't what molecular clock data directly shows.

Answer:

Clams and squid have been evolving separately for a shorter time than clams and snails.